It’s a short, fast-paced workout awesome for increasing flexibility and building core strength while also reaping the power-gaining benefits of hill running. USA Triathlon coach Jessica Herschberg, of FTP Coaching in Nashville, Tenn., says her athletes can barely make the 10 rounds.

Proper Kettlebell Form

Place the kettlebell between your feet. Hinge at the hips as if you are about to sit in a chair and bend the knees until your hands can grasp the handle. Start the swing by popping the hips forward until your knees are locked out, glutes tight and kettlebell reaches chest height.

Let the kettlebell swing back between your legs, hinging again at the hips, and letting your wrists hit the sides of your groin so the kettlebell is tucked right underneath the buttocks. Immediately and explosively pop your hips forward again to perform the next rep.

“You should feel this in your hamstrings,” Herschberg says. “Make sure you are looking forward so your shoulders aren’t rounded.”